Method and apparatus for applying a corrosion-resistant coating to fasteners

Abstract

A method of applying a corrosion-resistant coating to a fastener that includes preheating an area of the fastener to be coated to elevate a temperature of the area and spraying the preheated area of the fastener with a molten or semi-molten metal. In one embodiment, a corrosion-resistant coating applicator includes a support structure, a rotatable slotted fastener conveyer supported by the support structure, a feeder configured to feed fasteners to the rotatable slotted fastener conveyer, a fastener aligner configured to make head portions of the fasteners aligned with each other, a heater configured to heat head portions of the fasteners as the fasteners are being conveyed by the slotted fastener conveyer, and a sprayer configured to apply a corrosion-resistant coating to the heated head portions of the fasteners being conveyed by the slotted fastener conveyer. The present disclosure also provides corrosion-resistant coated fasteners made using the coating methods and/or coating apparatus.

The invention is claimed as follows: 
     
       1. A method of applying a corrosion-resistant coating to a fastener suitable for use within a power driving tool, the method comprising:
 feeding the fastener to a slotted fastener conveyor; 
 aligning a head portion of the fastener on the slotted fastener conveyor; 
 conveying the fastener along a perimeter of the slotted fastener conveyor; 
 preheating an area of the fastener on the slotted fastener conveyor to be coated to elevate a temperature of the area of the fastener to be coated; 
 spraying the preheated area of the fastener with a molten or semi-molten metal; and 
 dislodging the fastener from the slotted fastener conveyor. 
 
     
     
       2. The method of  claim 1 , wherein the sprayed metal provides a sacrificial cathodic corrosion protection to the pre-heated area of the fastener. 
     
     
       3. The method of  claim 1 , wherein the sprayed metal is selected from the group consisting of at least one of the following: zinc, aluminum, and alloys thereof. 
     
     
       4. The method of  claim 1 , wherein the fastener is made from a wire with a cathodic protection metal coating. 
     
     
       5. The method of  claim 4 , wherein the cathodic protection metal coating includes a hot-dip galvanization. 
     
     
       6. The method of  claim 4 , wherein the cathodic protection metal coating includes an electroplated coating. 
     
     
       7. The method of  claim 4 , wherein the metal spray is of substantially the same metal or alloy as the cathodic protection metal coating. 
     
     
       8. The method of  claim 1 , which includes one of sand blasting, grit or bead blasting, and shot blasting the area prior to preheating and spraying the area. 
     
     
       9. The method of  claim 1 , which includes applying a sealer to the area of the fastener after spraying the preheated area of the fastener with the molten or semi-molten metal. 
     
     
       10. The method of  claim 9 , which includes applying a top coat to the area of the fastener after applying the sealer to the area of the fastener. 
     
     
       11. A method of manufacturing a fastener made from a wire with a cathodic protection metal coating, the method comprising:
 feeding the fastener to a slotted fastener conveyor; 
 aligning a head portion of the fastener on the slotted fastener conveyor; 
 conveying the fastener along a perimeter of the slotted fastener conveyor; 
 heating the head portion of the fastener being conveying along the perimeter of the slotted fastener conveyor; 
 spraying a corrosion-resistant metal coating to the heated head portion of the fastener being conveying along the perimeter of the slotted fastener conveyor to coat the head portion with a sacrificial cathodic corrosion protection; and 
 dislodging the fastener from the slotted fastener conveyor. 
 
     
     
       12. The method of  claim 11 , which includes holding the fastener to the slotted fastener conveyor via a magnetic force. 
     
     
       13. The method of  claim 11 , which includes blowing air at the head portion of the fastener before the fastener is heated. 
     
     
       14. The method of  claim 11 , wherein heating the head portion of the fastener being conveyed along the perimeter of the slotted fastener conveyor includes heating the head portion of the fastener with induction heating. 
     
     
       15. The method of  claim 11 , wherein heating the head portion of the fastener being conveyed along the perimeter of the slotted fastener conveyor includes heating the head portion of the fastener with open-flame heating. 
     
     
       16. The method of  claim 11 , wherein the corrosion-resistant coating is applied at a first angle, and which includes applying a second corrosion-resistant coating at a second angle to the head portion of the fastener being conveyed along the perimeter of the slotted fastener conveyor. 
     
     
       17. The method of  claim 11 , which includes blowing air across a shank portion of the fastener when the corrosion-resistant coating is applied. 
     
     
       18. The method of  claim 11 , which includes one of sand blasting, grit or bead blasting, and shot blasting the head portion of the fastener prior to heating and spraying the head portion of the fastener. 
     
     
       19. The method of  claim 11 , wherein the slotted fastener conveyor is rotatable, and which includes rotating the slotted fastener conveyor to convey the fastener along the perimeter of the slotted fastener conveyor. 
     
     
       20. The method of  claim 11 , which applying a sealer to the head portion of the fastener after spraying the heated head portion of the fastener with a molten or semi-molten metal. 
     
     
       21. The method of  claim 20 , which includes applying a top coat to the head portion of the fastener after applying a sealer to the head portion of the fastener.